Semester

Fall

Date of Graduation

2009

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Psychology

Committee Chair

K. Andy Lattal.

Abstract

In several studies, historically lower-rate responding has been found to be more persistent than historically higher-rate responding (e.g., Lattal, 1989; Nevin, 1974). In these studies, historical response-rate differences were generated by reinforcement schedules (e.g., fixed-ratio [FR] and differential-reinforcement-of-low-rates-of-responding [DRL]) that directly affect response rate. The current study was conducted with pigeons pecking keys to determine whether this finding would hold when response-rate differences were generated by the context of reinforcement, such as a concurrently available source of reinforcement or schedule of response-independent food. In each of 3 experiments, a history-building condition was followed by a history-testing condition. In Experiment 1, history building consisted of a multiple-concurrent (variable interval [VI] 40-s VI 20-s, VI 40-s VI 80-s) schedule, and history testing consisted of a multiple fixed interval (FI) 40-s, FI 40-s. It was expected that response rate would be lower on the VI 40-s schedule that was paired with the VI 20-s than the VI 40-s that was paired with the VI 80-s (cf. Belke, 1992), however, large differences in response rate on the two VI 40-s schedules were not obtained. The rate and temporal distribution of historically lower-rate responding initially changed more rapidly than did higher-rate responding in each of the four pigeons. In attempt to increase the difference in response rate across the two components of the multiple schedule, in Experiment 2, history building consisted of a multiple concurrent (VI 40-s Tandem VI FR, VI 40-s Tandem VI DRL), and history testing consisted of a multiple (FI 40-s, FI 40-s). Schedule values were adjusted in attempt to obtain response-rate differences, but the programmed rate of reinforcement was always equal on the VI 40-s alternative across the two components. Again, large differences in response rate on the two VI 40-s schedules were not obtained. The rate of historically lower-rate responding changed more rapidly in three of the four pigeons, and the temporal distribution of historically lower-rate responding changed more gradually than did higher-rate responding. In Experiment 3, history building consisted of a multiple mixed VI 30-s variable time (VT) 30-s, VI 30-s schedule, and history testing consisted of a multiple FI 30-s, FI 30-s. The VT schedule provided the contextual schedule designed to reduce response rate in the same component. In this case, larger response-rate differences across the two components were obtained. Lower-rate responding was less persistent, both in terms of rate and temporal distribution of responding. Results are discussed in terms of factors shown to determine resistance to change, and the importance of understanding relations between schedules of reinforcement and resultant response organization.

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